"I wanted to be consistent with my exercise, so I committed to working out for 30 days in a row, no matter what," she tells Shape. "For an hour every day, I did something. I was on the elliptical or the treadmill, and if someone asked me to go to a class -- whether it was spinning, boxing, yoga, you name it -- I went."

Sims, who recently wed movie producer Scott Stuber, 42, eventually fell in love with the gym.